ext3 file losses? - Linux

This is a discussion on ext3 file losses? - Linux ; in ordered mode, ext3 filesystem, it seems to me that I once lost files from /usr/lib/* that I had not touched (write) in weeks during a crash. I believe that ext3 guarantees that files do not have stale blocks in ...

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  1. ext3 file losses?

    in ordered mode, ext3 filesystem, it seems to me that I once lost
    files from /usr/lib/* that I had not touched (write) in weeks during a
    crash.

    I believe that ext3 guarantees that files do not have stale blocks in
    them, which is nice. I wonder whether this means that there are
    scenarios in which ext3 can rearrange files somehow, and after the
    crash, just to make sure, it deleted any dubious /usr/lib/* files.

    My quandary is simple: I like the idea of journaling, and I also like
    the idea of (ext2) filesystem consistency checks (for other events).
    I want absolutely minimal chance of existing files disappearing, but
    do not care as much that the files I was just writing to may not
    survive a crash.

    unfortunately, ext3 in true journal mode slows to just about half
    writing speed (too much), and I seem to have lost files in ordered
    mode, if I am not hallucinating. (ext2 seemed very stable, even after
    crashes.) Am I hallucinating about file losses?

    advice appreciated.

    /iaw

  2. Re: ext3 file losses?

    I'm not sure where you heard that ext3 in journal mode is slow. It's
    actually pretty decent--I've been using it in this mode for a while and
    overall it "feels" faster than the other two modes.

    I would suggest that you read the "Advanced filesystem implementor's guide"
    at IBM developerWorks. It was written by Daniel Robbins, of Gentoo, and
    its 13 parts cover a variety of filesystems in fairly good detail. The
    parts that deal with ext3 (part 7 & 8) are here:

    http://www-106.ibm.com/developerworks/library/l-fs7/
    http://www-106.ibm.com/developerwork...ary/l-fs8.html


    Stu

    ivo welch wrote:

    > in ordered mode, ext3 filesystem, it seems to me that I once lost
    > files from /usr/lib/* that I had not touched (write) in weeks during a
    > crash.
    >
    > I believe that ext3 guarantees that files do not have stale blocks in
    > them, which is nice. I wonder whether this means that there are
    > scenarios in which ext3 can rearrange files somehow, and after the
    > crash, just to make sure, it deleted any dubious /usr/lib/* files.
    >
    > My quandary is simple: I like the idea of journaling, and I also like
    > the idea of (ext2) filesystem consistency checks (for other events).
    > I want absolutely minimal chance of existing files disappearing, but
    > do not care as much that the files I was just writing to may not
    > survive a crash.
    >
    > unfortunately, ext3 in true journal mode slows to just about half
    > writing speed (too much), and I seem to have lost files in ordered
    > mode, if I am not hallucinating. (ext2 seemed very stable, even after
    > crashes.) Am I hallucinating about file losses?
    >
    > advice appreciated.
    >
    > /iaw



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